Exterior square footage basics
For rectangular homes, approximate wall area as perimeter × average wall height. A 40×30 ft footprint with 9 ft walls ≈ 140 ft perimeter × 9 ft = 1,260 sq ft per story — adjust for gables, dormers, and garage.
Our house stain calculator uses footprint dimensions you enter plus wall height — refine with your actual measurements.
Two coats on exposed wood
Horizontal surfaces (decks, rail caps) weather faster than vertical siding. Most exterior stain systems recommend two coats on new or stripped wood, one maintenance coat on previously stained sound wood.
- Log homes: check log-specific coverage — often 100–150 sq ft/gallon
- Smooth hardboard siding: higher coverage than rough cedar
- Spraying: faster but uses more product — add 10–15% material